__
GOSS Toroidal Cores
High-efficiency grain-oriented silicon steel toroidal cores - available in standard sizes and fully custom configurations for high-power applications. Manufactured in the USA with low losses, minimal EMI, and scalable designs up to 800 kgs for BESS, datacenters, renewables, and industrial systems.
Custom GOSS Toroidal Cores -Standard & Large High-Power Designs
Bridgeport Magnetics manufactures high-efficiency custom GOSS toroidal cores for demanding power applications across industries. Our grain-oriented silicon steel toroidal cores combine continuous wound construction with superior magnetic performance, delivering low core losses, minimal electromagnetic interference (EMI), and compact high-power density.
From standard sizes to large custom toroidal cores engineered for BESS, datacenters, renewable energy systems, industrial power, and utility applications, every core is built to your exact specifications in our Shelton, Connecticut facility. Choose bare cores, epoxy fluidized, or polycarbonate film encapsulated – with fast US-based lead times and full vertical integration for quality you can rely on.
Why Choose GOSS Toroidal Cores for High-Power Applications
Grain-oriented silicon steel (GOSS) toroidal cores deliver exceptional magnetic efficiency with continuous wound construction. This design creates a near-perfect magnetic path, resulting in lower core losses, reduced electromagnetic interference (EMI), and higher power density compared to traditional laminated E-I cores.
For engineers designing larger systems, this translates to:
- Better energy efficiency in demanding applications
- Lower heat generation and reduced cooling requirements
- More compact footprints for space-constrained installations
Specifications
| /N | ID | OD | HT | BUILD | Finished Transformer Weight | Estimated VA Rating | V/TURN | % Voltage Drop |
|---|---|---|---|---|---|---|---|---|
| # | in | in | in | in | @ 60Hz 15kG | |||
| 0 | 1.375 | 2 | 1 | 0.313 | 0.43 | 46 | 0.077 | 17.5 |
| 10 | 1.5 | 2.375 | 1 | 0.438 | 0.7 | 77 | 0.107 | 11 |
| 20 | 1.625 | 2.875 | 1 | 0.625 | 1.16 | 130 | 0.153 | 8 |
| 30 | 1.75 | 3.25 | 1 | 0.75 | 1.55 | 180 | 0.184 | 6.7 |
| 40 | 1.875 | 3.375 | 1.125 | 0.75 | 1.83 | 233 | 0.207 | 6.3 |
| 50 | 2 | 3.5 | 1.25 | 0.75 | 2.12 | 295 | 0.23 | 6 |
| 60 | 2.125 | 3.75 | 1.375 | 0.813 | 2.7 | 396 | 0.274 | 4.7 |
| 70 | 2.25 | 4 | 1.5 | 0.875 | 3.38 | 522 | 0.322 | 4.5 |
| 80 | 2.5 | 4.375 | 1.5 | 0.938 | 3.98 | 690 | 0.345 | 4 |
| 90 | 2.625 | 4.5 | 1.625 | 0.938 | 4.47 | 824 | 0.373 | 3.8 |
| 100 | 2.75 | 4.875 | 1.625 | 1.063 | 5.42 | 1026 | 0.423 | 3.6 |
| 110 | 3 | 5.25 | 1.75 | 1.125 | 6.69 | 1392 | 0.483 | 3.5 |
| 120 | 3.25 | 5.5 | 2 | 1.125 | 8.11 | 1867 | 0.551 | 3.5 |
| 130 | 3.375 | 5.875 | 2 | 1.25 | 9.53 | 2237 | 0.613 | 3.3 |
| 140 | 3.5 | 6.125 | 2.125 | 1.313 | 11.06 | 2683 | 0.684 | 3 |
| 150 | 3.625 | 6.375 | 2.5 | 1.375 | 14.16 | 3548 | 0.843 | 2.7 |
| 160 | 4 | 7.125 | 2.5 | 1.563 | 17.9 | 4909 | 0.957 | 2.5 |
| 170 | 4.25 | 7.375 | 3 | 1.563 | 22.45 | 6650 | 1.149 | 2.3 |
| 180 | 4.375 | 8 | 3 | 1.813 | 27.72 | 8174 | 1.333 | 2.1 |
| 190 | 4.75 | 8.625 | 3 | 1.938 | 32.03 | 10300 | 1.425 | 2 |
| 200 | 5 | 9 | 3.5 | 2 | 40.38 | 13744 | 1.716 | 1.8 |
| 210 | 5.5 | 10 | 3.5 | 2.25 | 50.29 | 18710 | 1.93 | 1 |
| 220 | 6 | 11 | 3.5 | 2.5 | 61.29 | 24740 | 2.145 | 1.2 |
| L10 | 1.375 | 2.5 | 0.562 | 0.563 | 0.5 | 47 | 0.077 | 14.3 |
| L20 | 1.75 | 3.25 | 0.75 | 0.75 | 1.16 | 135 | 0.138 | 8.3 |
| L30 | 2.25 | 4 | 1 | 0.875 | 2.25 | 348 | 0.214 | 6.5 |
| L40 | 2.75 | 5.25 | 1.125 | 1.25 | 4.64 | 835 | 0.345 | 4.8 |
| L50 | 3 | 6 | 1.375 | 1.5 | 7.65 | 1458 | 0.506 | 3.1 |
| L60 | 4 | 7 | 1.5 | 1.5 | 10.2 | 2827 | 0.551 | 3 |
| L70 | 4.375 | 8 | 1.75 | 1.813 | 16.17 | 4768 | 0.777 | 2.6 |
| L80 | 4.75 | 8.625 | 2 | 1.938 | 21.35 | 6867 | 0.95 | 2.4 |
Toroidal Transformer Cores shine in high power density, versatile, low noise/EMI, high efficiency applications.
Battery energy Storage Systems (BESS)
High-efficiency BESS inverters & 480V 3PH Step-Down
Renewable Energy Inverters
Solar and wind power conversion
DataCenter UPS & Current Sensing
Reliable UPS systems for AI data centers
Industrial Automation
Heavy-duty motor drives and industrial inverters
Utility Metering and Protection
Precision grid metering and protection relays
Transformer Design Guidelines for GOSS Toroidal Cores
A17070 Design Information
As always in transformer design, you can vary the main parameters – duty cycle, frequency, induction level, and iron/copper ratio – to achieve your specific performance objectives.
Select the next larger core size to accommodate additional secondary windings, high voltage requirements, multiple tapings, or electrostatic screens. In every case, the actual power rating will differ from the standard 60 Hz / 15 kG values listed in the specifications table.
Autotransformer Performance
When used in autotransformer configurations (such as 120V/240V step-up or step-down), the power capacity is typically twice the listed VA rating.
These flexible design options make our custom GOSS toroidal cores ideal for engineers optimizing high-power solutions in BESS, datacenters, renewables, and industrial applications.
Let's build yours to spec.
Custom magnetics engineered and manufactured in the USA. Tell us your requirements and our engineers will help.
Frequently Asked Questions
How do I optimize power rating when designing with GOSS toroidal cores?
You can adjust key parameters like duty cycle, operating frequency, induction level, and iron/copper ratio to meet your exact performance goals. Selecting the next larger core size also provides headroom for more windings or higher voltage requirements.
Does the listed VA rating in the specifications table represent the maximum power?
No. The table shows standard 60 Hz / 15 kG values as a reference only. Actual power capacity will vary based on your chosen design parameters, frequency, duty cycle, and winding configuration.
Can GOSS toroidal cores be used in autotransformer applications?
Yes. In common 120V/240V step-up or step-down autotransformer setups, the effective power capacity is typically twice the listed VA rating, making them highly efficient for voltage conversion tasks.
What should I consider when choosing core size for high-power custom designs?
Consider secondary winding count, high-voltage insulation needs, tapings, and electrostatic shielding. A larger core often provides better thermal performance and flexibility for demanding BESS, datacenter, or industrial applications.
How does frequency affect the performance of custom GOSS toroidal cores?
Higher frequencies generally allow smaller cores or higher power density, while lower frequencies may require larger cores to avoid saturation. Our team can help calculate the optimal size for your specific frequency and induction requirements.
Are custom GOSS toroidal cores suitable for non-standard voltages and configurations?
Absolutely. We routinely produce cores for unique voltages, multi-tap designs, and specialized shielding. Contact us with your parameters and we’ll recommend the best core size and configuration.
